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Author Topic: absorption frig wont stay cold enuff while driving on 12v  (Read 1508 times)

tomrosa

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absorption frig wont stay cold enuff while driving on 12v
« on: July 16, 2014, 04:59:31 PM »
I have a three way frig in my '85 six pack cab-over that works great on 120V ac & gas (all tho very hard to start on gas). The problem is when I'm driving 2-8 hrs to the next camp site the frigs warms to 40-50*. The heater section is hot after the drive, just not hot enough?
Using gas does not work, the flame gets blown out and its illegal in CA.
So I tested the output and voltages. At the batteries of my '01 F250 with dual alternators I have about 14v. At the refrigerate I have 9.5v. Every connection from the factory relay, factory lines to the back of the longbed, connectors, junctions and switches loose a fraction of a volt. But they all add up.
Is 9.5V enough?
How can I keep my beer cold (and the other stuff) along the drive.
Why have 240A of current available if voltage is whats lost thru transmission?
Do I have to replace all the wiring with welding cable?
please help my ice cream stay icy and my beer stay frosty while I drive.

Gary RV_Wizard

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #1 on: July 16, 2014, 05:04:28 PM »
The output of the 12v heater is very dependent on voltage. Electrical power is measured in watts and watts = volts x amps. You need to diagnose the power circuits and clean up connections or maybe insufficient wire sizes to get the voltage up.

I don't believe your assertion that operating your fridge on LP gas is illegal in CA, but will yield judgment to those actually operating their RVs in CA.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

poncho62

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #2 on: July 16, 2014, 05:05:54 PM »
Maybe you just need more airflow over the coils of the fridge...that will keep it cooler. You can put a 12 volt fan in the chimney to draw more air through that area. I used a computer fan on my popup, made a world of difference. I was running on gas while travelling, not illegal here, just while gassing up, on ferries and in tunnels.
Hanover, Ontario, Canada

tomrosa

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #3 on: July 18, 2014, 07:59:41 AM »
Thanks for the input. I could not find anything specific to not running propane while driving. Now I just have to keep the flame lit. :)

Gary RV_Wizard

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #4 on: July 18, 2014, 08:43:38 AM »
Your 12v system should be operating at around 13.1-14.5 volts while driving (engine alternator running). That will power the 12v heater easily. You need to find and fix that massive voltage drop between the alternator output and the fridge. Undersized wiring and poor connections are the likely cause.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Lou Schneider

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #5 on: July 18, 2014, 11:39:08 AM »
The refrigerator likely draws about 30 amps in 12 volt mode - it doesn't take much to lose 4.5 volts between the alternator and the fridge.  Somewhere around 1.5 ohms total resistance will do it.

Marsha/CA

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Re: absorption frig wont stay cold enuff while driving on 12v
« Reply #6 on: July 18, 2014, 12:12:03 PM »
I had a 3 way fridge in our '93 truck camper.  The 12 volt never did keep anything cold; but it would draw my battery down in a heart beat.  The fridge worked great on electric and propane. 

Also, I live in California and have not heard that you cannot drive with the propane on.  We do it all the time.

Marsha~
2017 Heartland Mallard IDM231 Travel Trailer....Small but mighty.

 

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